A wash process in a conventional Washer Extractor consists of several steps, including one or more prewash, wash and rinse steps. These steps are carried our consecutively.
A conventional CBW consists of separate prewash, wash and rinse zones. Fresh water is introduced into the rinse zone of the machine and is passed cascade-fashion toward the mainwash zone while the laundry is transported in a countercurrent direction. These steps are carried out sequentially while the wash load is transported.
The detergent compositions used in such machines generally comprise products such as a prewash product, a main wash product, a bleach product and a neutralising product. Also one or more additional products, boosters, could be added to the process to enhance the detergency.
Typical product ingredients are surfactants, sequestering agents, such as phosphates, alkalinity salts, and bleaching agents.
Usually applied bleaching agents are hypochlorite, hydrogen peroxide and peracetic acid.
Contact time of the cleaning composition with the laundry in CBW's is typically quite short, e.g. about 1 to 2 minutes per wash segment.
The cleaned laundry is generally rinsed in a final rinse.
A problem observed when using the above-mentioned generally applied bleaching ingredients is the resulting considerable textile damage, occurring after multiple washings.
The main reason is considered to be the aggressive conditions in the wash for the textile. Both the wash temperatures (of generally 70-90.degree. C.) and the pH are high and the bleaching agents aggressive. These conditions are necessary to obtain adequate cleaning performance and hygiene.
Besides the negative impact on the textile, there are also other negatives associated with the high temperatures applied in the known CBW's of the prior art:
the wash processes require a high amount of energy. PA1 washing polyester cotton textile requires a specific and additional step to the wash process, called cool-down, to prevent creasing of the textile. Over a specific period of time colder water needs to be added to the wash to slowly cool the temperature to below 50.degree. C. This additionally increases wash times and requires more water. PA1 The aggressive products used are difficult to rinse out and high amounts of water in the rinse are required to eliminate these products from the textile. PA1 Not all articles can withstand these high temperatures. In particular, colour damage may easily occur. PA1 Effluant temperatures are high which is often not tolerated by authorities for environmental reasons. Authorities insist more and more on low temperatures of the effluent before it may enter any sewage system. PA1 wherein PA1 X is H, a halogen or a carboxyl group in any position on the aromatic ring; PA1 R is a straight or branched chain lower alkylene having 1-4 carbon atoms; and PA1 n is an integer in the range from 1-12, PA1 wherein the first component is introduced into a prewash zone or step, and the second component is introduced into a main wash zone or step. PA1 (i) formulating at least two separate components of a chemical cleaning system for aqueous dissolution or dilution to respective use concentrations, a first component comprising a proteolytic enzyme, and a second component comprising an imidoperoxycarboxylic acid of formula (I) (as defined in claim 1); PA1 (ii) introducing the first component into a prewash zone or step, to clean dirty laundry; PA1 (iii) introducing the second component into a main wash zone or step, to effectively complete the cleaning of the laundry.
We have now surprisingly found that these and other problems can be overcome, when applying a cleaning system having (in addition to a main wash product and a neutraliser) at least two separate components, a first component comprising a proteolytic enzyme and a second component comprising an imidoperoxycarboxylic acid bleach ingredient according to the present invention, wherein the first component is introduced into a prewash zone or step, and the second component is introduced into a main wash zone or step. These components are effectively used together with a main wash product and a neutraliser. An optional booster could also be added.